The present invention relates to a speed regulator for reducing a closing speed of an automatically closing slide door configured to automatically close from an opened position to a closed position.
Conventionally, an automatically closing slide door is known which is configured to automatically close from an opened position to a closed position. Such a door is automatically closed in many ways. For example, the opened door is closed by a thrust force exerted by an elastic member or is pulled in the closing direction by a weight or the like, or the door is suspended via a door roller from a rail inclining downward from the opened position to the closed position so that the slide door travels due to the self weight in the direction of closing the slide door.
Since the closing speed of such automatically closing slide door, if uncontrolled, gradually increases because of the acceleration by the thrust force exerted by the elastic member, by the descending weight, or by the weight of the slide door itself, there could occur a trouble that the door bumps a doorframe or the like at its highest speed when the door reaches the closed position. Despite of the trouble, such automatically closing slide door is often used, for example, at hospitals, homes for the aged or the like. Since sick people, those using wheelchairs or old people at the homes for the aged can not act as quickly as ordinarily healthy or young people, they sometimes fail in passing the automatically closing slide door while it is open. Further, especially in an automatically closing slide door configured to close by the weight or by its self weight, the automatically closing slide door reaches its highest speed just before the closed position due to the acceleration. Therefore, a noise is likely to occur when the door closes and a finger may possibly be clamped (hereinafter referred to as xe2x80x9cfinger clampingxe2x80x9d).
To solve these problems, for example, the Japanese Utility Model Laid-Open Disclosure No. H1-22070 discloses an automatically closing slide door which is provided with a shock absorber for reducing the impact caused by the door when closed so as to close the door quietly. Further, the Japanese Utility Model Laid-Open Disclosure No. H5-42564 discloses a device for preventing the finger clamping at the moment when the door closes. The device has a pinion gear mounted on a slide door and a rack mounted on a rail of the slide door and they are configured to be engaged and disengaged with each other so as to provide a speed reduction zone where the rotating speed of the pinion gear is reduced by a rotary oil damper coupled to a main rotatable shaft of the pinion gear.
Further, the Japanese Patent Laid-Open Disclosure No. H1-190888 discloses a device which closes a slide door using a spring force from a tightly-wound spiral spring. To apply brakes to the closing door, a DC-motor is employed as a generator which is utilized to work as a speed regulator. This allows the slide door to travel almost at a constant speed in the closing direction from the opened position to the closed position. Further, in this case, the speed of the closing door can be regulated on the site by adjusting the resistance value of a resistor which is connected between the input terminals of the DC motor so as to make a short-circuit there between, if necessary. Further, the Japanese Patent Laid-Open Disclosure No. H8-93316 discloses, for example, a bake device for a slide door or the like, which is configured to close a slide door by utilizing a potential energy to be supplied while the slide door is traveling along a rail provided with a small difference in the height between an opened position and a closed position. This brake device has a rack-and-pinion mechanism installed between a slide door and a doorframe for mounting the slide door and a generator for generating electric power by utilizing the closing action of the slide door, and brakes the closing slide door by utilizing an attracting force working between an electromagnetic force produced at a generator coil and a permanent magnet arranged around the generator coil.
Further, a speed reducer disclosed in the Japanese Patent Laid-open Disclosure No. H2-20784 operates speed regulating means for braking an automatically closing slide door during the slide door closing in such a way that a speed increasing gear train with a low speed increasing ratio is coupled to the speed regulating means for the initial stage of the door closing so as to produce a small braking force which allows the slide door to be closed at a relatively high speed, while another speed increasing gear train with a high speed increasing ratio is coupled to the speed regulating means so as to produce a large braking force which allows the slide door to be closed at a relatively low speed for the final stage of the door closing.
Although the way described above which reduces the impact at the moment of door closing by using a shock absorber or the like can control the door speed just before the final closing of the door, the closing speed of the slide door gradually increases during the period from the start of door closing until the shock absorber or the like begins to operate, which may sometimes give fear to a person passing the door, especially to an aged person. Further, those using wheelchairs or walking on crutches may suffer from such a trouble that the slide door bumps them because they cannot stop the door while they are passing the door.
Further, since a speed regulator employing the generator described above travels at a constant speed from the opened position to the closed position, the regulator cannot solve such problems as the finger clamping and the noise.
Further, when the slide door travels at a relatively high speed during the initial stage of the door closing and travels at a relatively slow speed during the final stage of the door closing, such traveling speed may be suitable under some conditions but may be unsuitable under other conditions.
Therefore, the object of the present invention is to provide a speed regulator for an automatically closing slide door which can reduce the closing speed of the slide door to the most suitable one for a person passing the slide door without causing problems such as the bump against the slide door, the finger clamping and the closing noise.
The object of the present invention can be achieved by a speed regulator for regulating a closing speed of an automatically closing slide door, comprising; a generator associated with said slide door; one-way clutch means for converting a linear movement of said slide door while closing into a rotational movement and for transmitting said rotational movement to said generator; a resistor connected to an output of said generator; and speed change means for changing a closing speed of said slide door, at a predetermined position before a closed position of said slide door, from a first predetermined speed to a second predetermined speed which is slower than said first predetermined speed by changing a resistance value of said resistor.
In the speed regulator for an automatically closing slide door according to the present embodiment, the movement of the slide door is not transmitted to the generator due to the one-way clutch means when a slide door is being opened. On the other hand, when the slide door starts to travel in the closing direction, the one-way clutch means converts the linear movement of the slide door into the rotational movement by which the generator is rotation ally driven. The mechanism for producing electric power in the generator is constructed such that a coil is rotated in a magnetic field to generate a voltage in the coil so as to produce a current. This mechanism is also applied to the present invention, wherein a rotary shaft is rotated in a magnetic field to produce electric power, the generated voltage gets higher with the increase in the revolution speed and a braking force substantially acts on the rotatable shaft of the generator when a large power is consumed. This braking force is transmitted to the one-way clutch means and is then applied to the linear movement of the slide door, and whereby the closing speed of the automatically closing slide door is reduced to the first predetermined speed.
After traveling at the first predetermined speed over a certain distance toward the closed position, the slide door reaches the predetermined position located before the closed position thereof, where the resistance value of the resistor applied to the output of the generator is reduced by the speed change means. This causes more current to flow and consequently a larger load is applied to the generator to increase the braking force and whereby the closing speed of the slide door is further decelerated to the second predetermined speed which is lower than the first predetermined speed, and travels to the closed position at this low speed
The automatically closing slide door used in the present invention may be any type of automatically closing slide door whose closing speed is controlled, including a slide door which closes at a substantially low speed using a thrust force exerted by an elastic member or a motor, not limited to such slide door which is pulled in the closing direction by the weight or the like, or which is accelerated by its own weight on an inclining rail while being closed. The resistor may be either of a fixed resistor with a predetermined resistance value or a variable resistor with a variable resistance value. Further, in order to reduce the speed between the predetermined position and the closed position, one variable resistor may be provided so that the resistance value thereof is changed by speed change means, or two resistors, each having different resistance values may be provided so that the resistors are switched to each other by the speed change means. Further, the closing speed may be reduced in two stages from the first predetermined speed to the second predetermined speed at the predetermined point before the closed point, or may be reduced in multi-stages more than two stages, or also may be reduced gradually while the slide door is traveling from the predetermined position before the closed position to the closed position. Further, the generator may be mounted either on the slide door or on a stationary frame attached to a building.
According to the present invention, the closing speed of the automatically closing slide door is decelerated to a desired speed and then, closed completely. Therefore, no problem takes place such as that the slide door gives fear to a person passing the slide door or the slide door bumps to the person. Further, since the closing speed of the slide door is further reduced at the predetermined point before the closed position of the slide door, such problems as the finger clamping and the closing noise can be prevented. Further, since the present invention uses the generator and the resistor connected to the output of said generator for reducing the speed of the slide door, neither the power supply nor the wiring is necessary, and the speed regulator can easily be installed in an existing slide door even if there is no power supply near by.